As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF SPEEDBUG WOULD NOT FOLLOW LOADED SPEED IN FMC WITH VNAV ENGAGED AND INDICATING. DURING CRUISE RECEIVED:VNAV PERF - INVALID". NOTICED LOST INDEX ON PERF PAGE WAS ERASED. ENTERED PLANNED LOST INDEX AND RESUMED NORMAL OPERATION. GROUNDED - YES. PER VERBAL FROM CREW AFTER CONFIGURING AC TO CORRECT CONFIG NO DEFECTS WERE NOTED NO HISTORY PREVIOUS 30 DAYS.